Over the years we have gradually become more convinced that the conventional approaches to creating paths over very soft ground do not work very well. They tend to be expensive to implement, very labour intensive, are disruptive, and are sometimes very intrusive visually. Floating roads and paths are not new by any means. What the North Harris Trust is doing is taking a tried and tested product and using it outside the parameters for which it was originally designed. By spreading the weight of a walker over a much larger footprint area, the soft substrate is capable of supporting the walker. The “Grass Protecta” mesh we are trialing is 14mm thick and offers a good balance between flexibility and support. It can accommodate surface irregularities yet on all but the softest ground, it can support in excess of 75 kg across a 1 width of track.
A great advantage of this technique is that the “turf” of the blanket bog and wet heath, a mixture of mosses, grasses, sedges, and heather, remains intact. The roots of all the plants forming a dense fibrous mat over the underlying wet and waterlogged peat. If the “turf” is cut through, the peat below can support virtually no weight, certainly not the pressure exerted on the ground by a typical person when walking. The open nature of the mesh allows grass and other vegetation to grow up through the mesh quickly. Over the course of a few growing seasons, the Grass Protecta will become completely en-meshed with the growing vegetation, providing a very tough but fully permeable reinforcement of the turf, which will tolerate a high volume of foot traffic and provide support across the whole path width.
Before going ahead with this experiment the Trust had detailed discussions with Paul Munday, the technical advisor on Grass Protecta for Boddingtons (the manufacturer), who have generously provided the materials for this trial. The first roll was installed in Glen Langadale in April and a further section went out a few days ago. In the intervening 18 days, grass and heather shoots had already started to grow up through the mesh apertures. If, as is hoped from the early indications, the trail proves successful, the Trust has plans to improve extensive sections of existing paths and to create new paths across soft ground that would otherwise be very expensive or completely impractical so to do.
